U.S. patent number 7,764,157 [Application Number 10/555,153] was granted by the patent office on 2010-07-27 for transformer.
This patent grant is currently assigned to Power Systems Technologies, GmbH. Invention is credited to Michael Becks, Olaf Blomker, Peter Grad, Andreas Kniesel, Wolfgang Lodde, Hans-Jurgen Mans, Reinhold Schulz.
United States Patent |
7,764,157 |
Schulz , et al. |
July 27, 2010 |
**Please see images for:
( Certificate of Correction ) ** |
Transformer
Abstract
The present invention relates to a transformer with a coil body
accommodating at least one primary coil and one secondary coil. It
is the object of the present invention to provide a transformer
which, using the smallest possible amount of high-grade insulation
material, ensures good insulation while remaining compact and
easily assembled. The object is achieved by a transformer of the
above type which is characterized in that the coil body comprises
at least one primary part, accommodating the primary coil, and one
secondary part, accommodating the secondary coil, and wherein at
least one section of the primary part can be covered by at least
one section of the secondary part. This section of the secondary
part performs the function of the fire-protection housing for the
primary part of the transformer.
Inventors: |
Schulz; Reinhold (Harsewinkel,
DE), Mans; Hans-Jurgen (Greven, DE), Becks;
Michael (Telgte, DE), Kniesel; Andreas (Munster,
DE), Grad; Peter (Munster, DE), Lodde;
Wolfgang (Munster, DE), Blomker; Olaf (Warendorf,
DE) |
Assignee: |
Power Systems Technologies,
GmbH (Ostbevern, DE)
|
Family
ID: |
33426929 |
Appl.
No.: |
10/555,153 |
Filed: |
May 6, 2003 |
PCT
Filed: |
May 06, 2003 |
PCT No.: |
PCT/EP03/04760 |
371(c)(1),(2),(4) Date: |
February 06, 2007 |
PCT
Pub. No.: |
WO2004/100192 |
PCT
Pub. Date: |
November 18, 2004 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070126545 A1 |
Jun 7, 2007 |
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Current U.S.
Class: |
336/198 |
Current CPC
Class: |
H01F
5/02 (20130101); H01F 5/04 (20130101); H01R
13/6675 (20130101); H01F 27/325 (20130101); H01R
13/6633 (20130101) |
Current International
Class: |
H01F
27/30 (20060101) |
Field of
Search: |
;336/65,107,192,198,200,232 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 364 811 |
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Apr 1990 |
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EP |
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1 240 795 |
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Jul 1971 |
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GB |
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1 250 827 |
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Oct 1971 |
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GB |
|
Other References
Lodestone Pacific bobbin specifcation. cited by examiner.
|
Primary Examiner: Nguyen; Tuyen
Attorney, Agent or Firm: Crouch; Robert G. Marsh, Fischmann
Breyfogle, LLP
Claims
The invention claimed is:
1. A transformer, comprising: at least one AC contact pin for
contacting a mains voltage; and a coil body accommodating at least
one primary coil and one secondary coil, wherein the coil body
comprises at least one primary part accommodating the primary coil
and one secondary part accommodating the secondary coil and wherein
at least a region of the primary coil of the primary part is
coverable by a least one section of the secondary part, wherein the
secondary part includes a fire-protection material which is a
plastic material of the fire-protection class UL94-V1 or better,
wherein a connection region of the primary part is electrically
connected to the at least one AC contact pin at an intersection,
and wherein said intersection is covered by an associated
insulation part which forms part of the secondary part.
2. The transformer according to claim 1, wherein the primary part
and the secondary part are designed as two separable parts.
3. The transformer according to the claim 1, wherein said at least
one section of the secondary part has an internal diameter which is
greater than an external diameter of said at least one coverable
section of the primary part.
4. The transformer according to claim 1, wherein the primary part
is connected to the at least one contact pin via a one-way plug
connection.
5. The transformer according to claim 4, wherein the one-way plug
connection has at least one locking element which engages the
primary part in a connection region from behind.
6. The transformer according to claim 1, wherein said at least one
contact pin has an insulated sheath region.
7. The transformer according to claim 1, wherein the connection
region comprises a connection tab, and wherein the associated
insulation part covers substantially an entire length of the
connection tab.
8. The transformer according to claim 1, further comprising a
housing that at least partially encompasses the at least one AC
contact pin and the coil body, wherein the housing comprises a
material of a fire-protection class that is lower than the
fire-protection class of the plastic material of the secondary
part.
9. The transformer according to claim 1, wherein said associated
insulation part at least partially covers the at least one AC
contact pin.
10. The transformer according to claim 1, wherein the primary part
comprises a primary spool for accommodating the primary coil and
wherein the secondary part comprises a secondary spool for
accommodating the secondary coil; wherein the secondary spool and
secondary coil do not cover the primary spool and primary coil.
Description
The present invention relates to a transformer with a coil body
accommodating at least one primary coil and one secondary coil.
Transformers of the above type are used e.g. to supply a low
voltage to high-volume consumer products. To comply with whatever
safety standards are in force, such transformers are enclosed in a
housing made of a plastic material of the fire-protection class
UL94-V1 or better. Such insulation materials are, however,
relatively expensive. Many manufacturers therefore seek to minimize
the use of these high-grade materials.
An example of this is referred to in the European patent
application No. 01 309 737.3. Here the insulation of a transformer
is provided by a second covering made of fire-protection material,
in addition to a main housing made of simple material. The second
covering encloses part of a primary coil of the transformer and
connection pins which extend from the primary coil. This
arrangement is relatively complicated, particularly as regards the
assembly of the transformer. Furthermore, the size and the weight
of the power supply unit increase due to the additional second
covering.
It is the object of the present invention to provide a transformer
which, using the smallest possible amount of high-grade insulation
material, ensures good insulation while remaining compact and
easily assembled.
This object is achieved by a transformer of the above type which is
characterized in that the coil body comprises at least one primary
part, accommodating the primary coil, and one secondary part,
accommodating the secondary coil, and wherein at least one section
of the primary part can be covered by at least one section of the
secondary part.
This transformer has the advantage that the secondary part has a
double function. Firstly, it carries the secondary coil. Secondly,
at least one section of the secondary part serves to cover at least
one section of the primary part, thus enabling the secondary part
to provide insulation and the function of fire-protection for said
at least one section of the primary part. As a result of the
transfer of both these functions to the secondary part of the
transformer, there is either no need for additional coverings or
their number can be reduced. The transformer can thus be made
compact and light and its assembly can be simplified.
According to an advantageous embodiment of the invention at least a
region of the primary coil can be covered by the secondary part.
Insulation of said at least one region of the primary coil can thus
be achieved.
In a preferred example of the invention at least a contact pin
region of the primary part can be covered by the secondary part.
This construction has the advantage that at least a part of the
contact pin region can be insulated.
According to a favourable variation of the invention the primary
part and the secondary part are designed as two parts which can be
separated from each another. This enables the secondary part to be
moved relative to the primary part, so that said at least one
section of the secondary part can easily be superimposed on said at
least one section of the primary part so as to cover it.
Advantageously, said at least one section of the secondary part has
an internal diameter which is greater than the external diameter of
said at least one coverable section of the primary part.
Consequently, said at least one section of the secondary part can
be superimposed on or pushed onto said at least one coverable
section of the primary part, thus ensuring that this section of the
primary part is well covered.
In a further preferred embodiment of the invention the secondary
part consists of a fire-protection material. With this construction
the secondary part can perform a fire-protection function.
According to a further advantageous embodiment of the invention the
fire-protection material is a plastic material of the
fire-protection class UL94-V1 or better. This material ensures
particularly good fire-protection which complies with the required
safety standards in a number of countries.
The primary part is preferably connected to at least one contact
pin which is covered at at least one connection region to the
primary part. With this arrangement, said at least one contact pin
in the connection region to the primary part can be insulated and
also fixed in position.
In a further favourable embodiment of the invention the primary
part is connected to at least one contact pin by means of a one-way
plug connection. The one-way plug connection ensures that once a
contact pin has been connected to the primary part it is held
firmly in place. In this way the contact pin can be fixed in
position and isolated from the user, even if the outer housing of
the equipment is damaged.
In a further example of the invention the one-way plug connection
has at least one locking element which engages the primary part in
a connection region from behind. Such a construction ensures simple
assembly of the contact pin with the primary part and a high degree
of stability of the connection between the contact pin and the
primary part.
The said at least one contact pin preferably has an insulated
sleeve region. This provides additional user protection against
contact with voltage-carrying and thus dangerous contact pins,
especially in the event of damage to the outer housing of the
equipment.
The present invention is described below in terms of advantageous
embodiments and making reference to the relevant figures of the
drawing, where
FIG. 1 shows a perspective view of a primary part and of a
secondary part of a transformer according to a first embodiment of
the present invention;
FIG. 2 shows a perspective view of an assembled transformer module
according to the first embodiment of the present invention;
FIG. 3 shows a perspective sectional view of an assembled
base-plate assembly with the transformer according to the first
embodiment of the present invention;
FIG. 4 shows a perspective view of a primary part and of a
secondary part of a transformer according to a second embodiment of
the present invention;
FIG. 5 shows a perspective sectional view of a transformer with a
one-way plug connection according to a third embodiment of the
present invention; and
FIG. 6 shows a schematic sectional view of the one-way plug
connection of the third embodiment of the present invention.
FIG. 1 shows a perspective view of a primary part 4 and of a
secondary part 5 of a transformer according to a first embodiment
of the present invention. In the first embodiment the primary part
4 and the secondary part 5 are, as is shown in FIG. 1, designed to
be separable parts and together they form a coil body 1.
In cross-section the primary part 4 has approximately the shape of
an "H". The left-hand section of the "H" in FIG. 1 constitutes a
connection section 42 of the primary part 4, the upper part of
which has a connection region 7 for AC contact pin contacting. The
middle region of the "H" comprises an approximately rectangular
spool with rounded edges. The spool serves to accommodate a primary
coil 2 which is wound thereon. The right-hand section of the "H" in
FIG. 1 constitutes a spool boundary 13 for the spool of the primary
part 4 on this side. It has a larger diameter d than the spool with
the primary coil 2 wound on it.
The primary part 4 is hollow inside. In the example shown the inner
opening 45 of the primary part 4 has a roughly rectangular
cross-section. The inner opening 45 later serves to house an iron
core (not shown in FIG. 1).
The secondary part 5, like the primary part 4, is approximately in
the form of an "H" which is hollow inside. The left-hand section of
the "H" in FIG. 1 has an internal diameter D which is larger than
the external diameter d of the spool boundary 13 of the primary
part 4. Its breadth B is approximately the same as the breadth b of
the spool and spool boundary of the primary part 4. The left-hand
section of the secondary part 5 in FIG. 1 later forms a cover
region 6 for the primary coil 2 of the primary part 4.
In a region of the secondary part 5 shown top left in FIG. 1, the
cover region 6 has insulation parts 11 for AC contact pins (not
shown in FIG. 1). The insulation parts 11 extend at an angle of
roughly 90.degree. to the direction of diametral extension D of the
secondary part 5. In the embodiment shown the insulation parts 11
have an internal cross-section of roughly rectangular shape and
they are hollow on the inside to provide covering for the AC
contact pins or for the connection region to the contact pins. In
other embodiments of the invention (not shown) the insulation parts
11 may be circular, elliptical or polygonal in cross-section,
preferably adapted to the form of the contact pins to be
insulated.
The "H" of the secondary part 5 has a middle region which serves as
a spool on which a secondary coil 3 is wound. Like the spool of the
primary part 4, the spool of the secondary part 5 is roughly
rectangular in cross-section and has rounded edges. It has an inner
opening 14 to accommodate an iron core (not shown in FIG. 1).
The right-hand section of the "H" of the secondary part 5 in FIG. 1
constitutes a spool boundary 15 for the secondary coil 3. The spool
boundary 15 has a larger diameter than the diameter of the spool
with the secondary coil 3 of the secondary part 5.
In a region of the spool boundary 15 shown at the bottom right in
FIG. 1 there are connection regions 16 to provide a connection to
DC contact pins 17.
The base material of the coil body 1, the cover region 6 and the
insulation parts 11 of the secondary part 5 are all composed of a
fire-protection material of the fire-protection class UL94-V1 or
better. The windings of the primary coil 2 and of the secondary
coil 3 are made of a metallic material, e.g. copper. The contact
pins are also made of a metallic material, e.g. bronze.
FIG. 2 shows a perspective view of an assembled transformer module
18 according to the first embodiment of the present invention. The
transformer module shown there is formed by assembling the primary
part 4 and the secondary part 5, depicted separately in FIG. 1. In
the composite structure the cover region 6 of the secondary part 5
covers the primary coil 2 of the primary part 4. Also the
insulation parts 11 of the secondary part 5 cover the corresponding
connection regions 7 of the primary part 4.
The internal diameter D of the covering 6 of the secondary part 5
being greater than the external diameter d of the primary part,
assembly of the primary and secondary parts was achieved by pushing
the secondary part 5 onto the primary part 4. In the resulting
composite the covering 6 of breadth B encloses the breadth b of the
primary coil 2 and the spool boundary, providing both good
electrical insulation for the primary coil 2 as well as good
fire-protection in accordance with the fire-protection material
employed.
In the embodiment shown also the insulation parts 11 were pushed
onto the connection regions 7 during assembly so that they enclose
them apart from the contact region. The insulation parts 11 serve
both to electrically insulate the connection regions 7 and to
provide fire-protection for the connection regions 7 in accordance
with the fire-protection material employed.
As shown in FIG. 2, the assembled transformer module 18 is compact.
Since dangerous current-carrying regions such as the primary coil 2
and the connection regions 7 are shielded by the covering 6 and the
insulation parts 11, the transformer module in the form shown in
FIG. 2 can be used without an additional fire-protection housing
and complies with the fire-protection requirements in a number of
countries despite its simple construction.
In the embodiment shown the coil body 1, composed of two halves,
performs a double function. Firstly, it accommodates the wire
windings of the primary coil 2 and of the secondary coil 3.
Secondly, the coil body 1 fulfils the fire-protection housing
function required by the regulations, whereby the use of additional
plastic coverings or housing components can be eliminated or
reduced. Due to the minimization of the material employed, the
manufactured transformer weighs little. From FIG. 1, which shows
the parts of a transformer module in the unassembled state, and
from FIG. 2, which shows the transformer module after assembly, it
can be seen that the transformer can be assembled simply by pushing
the secondary part 5 onto the primary part 4.
FIG. 3 shows a perspective sectional view of an assembled
base-plate assembly 12 with a transformer module 18 according to
the first embodiment of the present invention.
The transformer module 18 shown in FIG. 2 has an iron core 20
inserted into it. Furthermore, the transformer module 18 is built
into a housing 21 made of a conventional plastic material. Two
contact pins 8 project from a contact region 22 which protrudes at
an angle from the housing 21. The contact pins 8 traverse the
contact region 22 of the housing 21 and make electrical contact
with the primary part 4 of the transformer module 18. The contact
pins 8 are AC contact pins, which are meant to connect the
transformer module 18 to a socket (not shown) when in use so as
supply the transformer module 18 with AC voltage. Due to the use of
the insulation parts 11 in the connection regions 7 to the contact
pins 8 and also due to the use of the covering 6 in the transformer
module 18, the base-plate assembly shown in FIG. 3 is
fire-protected.
The contact pins 8 in FIG. 3 are elongate and of circular
cross-section and thus conform to a contact pin standard which is
typically used in Europe apart from Great Britain. The present
invention is not, however, restricted to such contact pins 8.
Instead of these, other forms of contact pins or more than two
contact pins can be used in the present invention.
FIG. 4 shows a perspective view of a primary part 24 and of a
secondary part 25 according to a second embodiment of the present
invention.
The primary part 24 is shown separated from the secondary part 25
in the unassembled transformer. The primary part 24 and the
secondary part 25 together form a coil body 41.
Much like the primary part 4 of the first embodiment of the
invention, the primary part 24 of the second embodiment of the
invention consists of a connection section 26, a spool 27 and a
spool boundary 28. The connection section 26 has two connection
regions 9, via which a connection to the contact pins 8 is
established. The contact pins 8 are shielded in the connection
regions 9 to the primary part 24, e.g. by encasing by means of
injection moulding. A plastic, preferably of the fire-protection
class UL94-V1, is used as injection-moulding material. Due to
encasing by means of injection moulding the contact pins 8 are
fixed in position relative to the primary part 24 and are
electrically isolated externally. Instead of encasing by injection
moulding, the connection regions 9 can, however, also be encased by
casting or by some other method.
The contact pins 8 in FIG. 4 are plate-shaped perforated contact
pins with beveled edges in a front region. They thus conform to a
contact pin standard in use e.g. in the USA, China and Japan.
However, instead of these contact pins other forms of contact pins
can be used, e.g. pins with a circular cross-section. Instead of
two contact pins, only one contact pin or more than two contact
pins can be provided.
The connection section 26 of the primary part 24 is followed by the
spool 27 with a primary coil 32 wound thereon. The spool 27 is
followed immediately by a spool boundary 28.
The secondary part 25 possesses a cover region 29 which is pushed
onto the primary coil 32 of the primary part 24 during assembly of
the coil body 41.
Much like the secondary part 5 of the first embodiment of the
invention, the cover region 29 has insulation parts 44 for covering
the connection regions 9 of the primary part 24. These are pushed
onto the corresponding connection regions 9 of the primary part 24
during assembly of the coil body 41 so as to enclose these. The
insulation parts 44 are, like the cover region 29, made of a
plastic material, preferably a fire-protection material of the
fire-protection class UL94-V1, and thus provide both electrical
insulation and fire-protection for the connection regions 9 after
assembly of the coil body 41.
The cover region 29 is followed by a spool 30 with a secondary coil
33 wound thereon. The spool 30 is bounded on the other side by a
spool boundary 31. Contact regions for DC contact pins 43 are
located on the spool boundary 31.
FIG. 5 shows a perspective view of a transformer according to a
third embodiment of the present invention.
Here a transformer module is, like the transformer module 1 of the
first embodiment of the invention, installed in a housing 36.
Contact pins 8 which are electrically connected to the primary part
4 within the housing 36 project from the housing 36.
The contact pins 8 are provided with an electrical insulation 37
which encloses at least a peripheral region of the contact pins 8
within the housing 36. The insulation 37 is made of plastic,
preferably a plastic of the fire-protection class UL94-V1 or
better.
The contact pins 8 are connected to the primary part 4 of the coil
body 1 within the housing 36 via a one-way plug connection 10. The
one-way plug connection 10 is plugged in once and for all during
assembly of the transformer and can subsequently only be disengaged
with difficulty, if at all, even when it is subjected to a very
strong tensile force, e.g. 50 N.
An example of the one-way plug connection 10 is shown in FIG. 6.
The one-way plug connection 10 is so designed that the contact
spring 46 is pushed onto the round contact pin 8. The contact
spring 46 is expanded as a result of this action. Due to the
restoring force of the contact spring 46 and the friction between
the contact spring 46 and the contact pin 8, the connection can
only be broken forcibly.
The one-way plug connection 10 is a safety plug connection, being
such that the contact pins 8 remain fixed in position and isolated
from contact by the user even if the outer equipment housing should
be damaged, e.g. through being struck or improperly used. Even when
the outer housing 36 has been damaged, the user can remove the
remaining unit, consisting of the contact pins 8 and the coil body
1 of the transformer, from a mains socket without endangering
himself since he cannot touch voltage-carrying and thus dangerous
parts.
Although the third embodiment of the present invention in FIG. 5
shows contact pins 8 according to the European standard, this
embodiment is also suited for use with contact pins or plug pins
conforming to other standards.
Although the transformer of the present invention consists of two
parts in the described embodiments, this is not necessary for the
third embodiment of the invention. The transformer can also be
implemented as a single-part coil body comprising a primary part
accommodating the primary coil and a secondary part accommodating
the secondary coil. The fire-protection function is provided by
additional plastic parts or tapes in this case.
* * * * *